Please advice me some good book on JCA (Java Connector Architecture) essentials and basics, which will cover all features like cci, etc.

Thank you!

P.S. Of course I understand it will not be free, I want to buy one! :-)

Theres:J2EE Connector Architecture and Enterprise Application Integration, Sharma, Stearns and Ng, Sun Press and Java Connector Architecture, Apte, Sams press The second book is a bit more useful. They're still both starting points - have a look on the web as well for stuff.